Extreme Ultraviolet Lithography (EUVL) typically employs light at an exposure wave length of about 13.5 nm and is the most promising next generation lithographic technology for high volume manufacturing of semiconductor microelectronics with resolution less than 20 nm. EUVL is based on reflective optics and a reflective photomask including a multilayer mirror. During exposure, light reflected from portions of the photomask outside the image pattern may stray into regions which adjoin the illumination field on a target substrate onto which the image pattern is projected and which are designated for a further exposure step. Typically, a black border or shadow frame suppresses leakage of exposure light reflected at portions of the photomask outside of the imaged pattern onto an illumination field designated for a later or previous exposure step on the target substrate.